Rates of women who are opting for preventive mastectomies, such as Angeline Jolie, have increased by an estimated 50 percent in recent years, experts say. But many doctors are puzzled because the operation doesn't carry a 100 percent guarantee, it's major surgery -- and women have other options, from a once-a-day pill to careful monitoring.

Psychologist Campbell Leaper of the University of California Santa Cruz conducted a review of research into the topic spanning from the 1960s to today and which is detailed in the November issue of the journal Personality and Social Psychology Review. The studies Leaper examined looked at talkativeness and different types of speech under a range of social situations and comparing mixed-gender and same-gender conversations.

One clear point that emerged from all the studies was that the type of activity people were engaged in influenced how much they talked.

"So even though on the average we're finding a slight trend toward men being more talkative than women, we found larger differences when you looked at particular situations," Leaper said.

During decision-making tasks, men were more talkative than women, the studies showed, but when talking about themselves or working with children, women were more talkative than men.

Leaper said that these gender differences could have to do with differences in gender socialization; typically, women are socialized to be more comfortable talking about their feelings, while men are socialized to be dominant and take charge.

"One gender isn't inherently more talkative than the other, it's just that a lot of times it depends on the situation and gender role influences," Leaper said.

A recent study in the journal Science that recorded conversations of university students supports Leaper's idea, finding that on average, men and women used about the same number of words per day. (Leaper said that studies that used this measure of talkativeness tended to find less difference between men and women than studies that looked at how much time people spent talking. In these latter studies, men used up more time in the conversation than women, Leaper said.)

Talkativeness was also influenced by whether a person was talking to someone of their same gender or the opposite gender.

"Men tend to be more talkative than women, but particularly when they're interacting in mixed-gender settings," Leaper said, explaining that this could also be a result of men traditionally being socialized to dominate.

The situation was reversed when looking at different types of speech, specifically assertive (used to achieve dominance and goals) and affiliative (used to connect to others): differences emerged in how much these types of speech were used when comparing two men talking to each other to two women conversing than when a man and a woman were talking.

These differences have actually declined with time though.

"In terms of styles of communication, gender differences are decreasing," Leaper said. "My interpretation is that it reflects the historical changes in gender roles," with women coming into the workplace more and men being more open about their feelings.